Hitherto known alkoxysilane compounds of the type which contain a styrene skeleton are vinylbenzyltrimethoxysilane (Masanori Kokubo et al., Kohbunshi Ronbunshu, volume 36, page 201 (1981)), vinyl phenyltrimethoxysilane (Y. Kawakami et al., Polymer Journal, volume 17, page 1159 (1985)) and so on. In the syntheses thereof, however, it is necessary to use styrene type Grignard reagents which are quite unstable and liable to polymerize (namely, vinylbenzylmagnesium halide in the former compound, and vinylphenylmagnesium halide in the latter compound). Therefore, the syntheses of such compounds on an industrial scale are very difficult. In addition, since the syntheses of the foregoing compounds require a large quantity of solvent and a process of removing salts through filtration, they are at a disadvantage in entailing high cost of manufacturing.
As for another styrene skeleton-containing alkoxysilane, vinylphenetyltrimethoxysilane is known to be obtained by hydrosilylation of divinylbenzene with a hydrogensilane (G. Greber, Makromol. Chem., volume 53, page 19 (1962)). In general, the hydrosilylation method is said to be suitable for syntheses of functional group-containing alkoxysilanes in respects of low cost and good working efficiency, because it does not use any solvent and does not require any filtration process. In case of the above-cited compound, however, divinylbenzene used as a starting material is extremely unstable and apt to polymerize and, what is worse, it has a disadvantage in that there is a tendency for addition of two silane molecules upon hydrosilylation because of the presence of two vinyl groups almost equivalent in reactivity in the substrate, whereby a yield of the intended compound is lowered.
As a result of our intensive study with the intention of obviating the above-described defects, it has been found that the hydrosilylation can be effected with ease by the use of 3-(vinylbenzyloxy)-1-propenes as a starting material and can provide styrene skeleton-containing alkoxysilane compounds at a low price, and the compounds obtained herein are novel compounds, thus achieving the present invention.